Yesterday's Tractor Co. Parts for Farm Tractors - Compare our Prices!
Click Here or call 800-853-2651 
   Allis Chalmers Case Farmall IH Ford 9N,2N,8N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   Traditional YT Forum ViewClassic View   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Coil 3400


 
Post new topic    
View previous topic :: View next topic  
Author Message
Billy the kid
Regular


Joined: 04 Dec 2010
Posts: 57


Report to Moderator

PostPosted: Thu Nov 15, 2012 3:16 am    Post subject: Coil 3400 Reply to specific post Reply with quote

1st I want to say thanks for all the help.
I still am a little Confused about one thing.
Why would you need a resister with a 6 volt coil
but I can replace with a 12 volt coil and not need one?
Does the new 12 volt coil have one built in to the coil?
 
Back to top
View user's profile
Keith Williams
Long Time User


Joined: 12 Mar 2008
Posts: 716
Location: Eastern Ohio

Report to Moderator

PostPosted: Thu Nov 15, 2012 4:49 am    Post subject: Re: Coil 3400 Reply to specific post Reply with quote

Billy the kid,
First lets start with:
"Well I have power at the coil on start and run. I tested with a test light. I guess I need to put a volt meter on the coil input wire to see what I get.
When I jump the coil the old girl will run."

When you jumped the coil, You supplied power. It must have not had enough power already!

"Why would you need a resister with a 6 volt coil
but I can replace with a 12 volt coil and not need one?"

Long story short. You need a certain amount of current to run through the circuit (as in Amps) to create a spark. Amps equals volts divided by resistance. The problem is volts are different when you start vs when running. Maybe 8 volts left when you crank the engine. Around 14 volts when the engine is running and the charging system is working.

So the old way to do that on a 12 volt system was to run two wires to a low resistance coil (called a 6V coil). Wire number 1 came from the starting circuit, since the voltage is low when starting, no additional resistance is needed. Wire number 2 comes from the running circuit, you need resistance to limit the current, so they add a ballast resistor. In both cases the current is enough to create a spark.

Now the coils (called 12 volt) can be placed directly in the circuit and are able to produce a spark and limit current under both the start and running conditions with out additional resistance. These coils are marked "No resistance needed".

I hope this brings to light some of the info you need.
JMOR or several others can explain more if you need it. Just let us know if this is enough.
Keith
 
Back to top
View user's profile
souNdguy
Tractor Guru


Joined: 20 Aug 2002
Posts: 53847


Report to Moderator

PostPosted: Thu Nov 15, 2012 5:30 am    Post subject: Re: Coil 3400 Reply to specific post Reply with quote

Keith actually covered it pretty good.

them 3 cyl's used a 6v coil and a resistor wire. the r-wire was in the run circuit. at startup, the 6v coil was powered by full bat votlage.. or whatever was left after the starter took it's share.

there are various ways to do it. old fords used a thermall sensitive resistor.. newer setups could use a solenoid with a bypass line on it.. or simply a different tap off the key switch, etc.

newer oil potted coils can handle heat disipation better and thus can be run a lil hotter that an older dry or hard epoxy or even older hard tar-like potted coils.
 
Back to top
View user's profile
Billy the kid
Regular


Joined: 04 Dec 2010
Posts: 57


Report to Moderator

PostPosted: Thu Nov 15, 2012 6:16 am    Post subject: Re: Coil 3400 Reply to specific post Reply with quote

No think that will do it.
You guys are always a great help.
I was doing my 8n over last year and again this was a great place to get info!!!!!
 
Back to top
View user's profile
Display posts from previous:   
Post new topic    Yesterday's Tractors Forum Index -> Ford All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
TRACTOR   PARTS TRACTOR   MANUALS
Same-Day Shipping! Most of our stocked parts ship the same day you order (M-F).  Expedited shipping available, just call!  Most prices for parts and manuals are below our competitors.  Compare our super low shipping rates!  We have the parts you need to repair your tractor.  We are a Company you can trust and have generous return policies!   Shop Online Today or call our friendly sales staff toll free (800) 853-2651.

YT Home  |  Forums Home

Copyright © 1997-2014 Yesterday's Tractor Co.

Powered by phpBB © 2001, 2005 phpBB Group

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters